Electrical connector



Dec. 24, 1963 w. H. Mcm-:E 3,115,379

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ELECTRICAL CONNECTOR Filed NOV. 29, 1961 4 Sheets-Sheet 4 In venofwn/,4M H MaX/ff United States Patent O 3,115,379 ELECTRICAL CNNECTGRWilliam H. McKee, West Covina, Calif., assignor to United-Carr FastenerCorporation, Boston, Mass., a corporation of Delaware Filed Nov. 29,1961, Ser. No. 155,764 4 Claims. (Cl. 339-47) The present inventionrelates to an electrical circuit connecting device and more particularlyit relates to an improved contact element structure for electricalconnecting devices.

Most electrical connectors utilize complementary pairs of dissimilarcontact elements. Normally one unit of each pair is provided with femaletype contact elements or sockets adapted to receive male type elementsor prongs of the other unit of the pair. Such electrical connectorsrequire the manufacture of separate and distinct connecting implementsor elements for each complete connection. This entails the manufactureof the separate components and the stocking by distributors of differenttypes of elements for each type of connector.

The electrical connectors of the present invention are provided withpairs of prongs either of identical shape or mirror images when facingthe outer ends of interengageable pairs. Only one ty'pe of element needbe blanked in manufacturing, thus, facilitating manufacture of suchcomponents.

The `connectors of the present invention further embody features ofconstruction providing large area wiping interfacial contact areas uponengagement of mating units. These large wiping contact areas assure lowcontact resistance and preclude poor high resistance contact resultingfrom an insulating iilm, dust or small area engagernent.

Further in accordance with one aspect of the present invention,universal contact elements are formed of bifurcated resilient metalstampings, such `as phosphor bronze, having their fork-defining prongsoffset in two directions in relation to the :cent-ral line of theelement and effective to engage the mating .element in edge contact thatfiexes the prongs in both directions to provide resilient contact-makingengagement.

Another aspect of the present invention resides in the overlappinginterfacial areas of the fork-deiining prongs of each of the luniversalcontact elements.

It is accordingly a general object of the present invention to providean improved electrical connector wherein the interengaging elements areidentical in construction.

It is a further object of the present invention tol provide an improvedelectrical connector wherein the prongs or interengaging elements aremirror images of each other when facing the outer ends ofinterengageable pairs and are formed from the same blank material.

It is an additional object of the present invention to provide animproved electrical connector device having an improved prong orelectrical contact that provides a large wiping electrical contact areato the mating connector.

A further object of the present invention is to provide an improvedelectrical connecting device having a novel electrical Contact designwherein any one contact may be electrically mated with yany otherconnector.

An additional object of the present invention is to provide an improvedelectrical connecting device having improved electrical contacts, saidcontacts being constructed such that they provide universal joint actionwhen connected to facilitate easy insertion and withdrawal of thecontacts with relation to each other.

Still another object of the present invention is to provide an improvedcontact construction wherein prongs 3,115,379 Patented Dec. 24, 1963 ICCengage on their edge portions, they are spaced and flexed in twodirections in relation to the plane of 'the prongs, and yet no relianceis placed upon the presence of a bevel on the prongs.

A further object of the present invention resides in the provision of auniversal electrical connecting element for printed circuit boardshaving indexing members thereon for convenience in assembly.

It is still another object of the present invention to provide animproved electrical connecting device for printed circuit boards that iseasily mounted thereon and that provides an easy interengagement withmating connectors from mating circuits so that easy and convenientinsertion and withdrawal of the circuits and connectors may be realized.

Yet another object of the present invention is to provide an improvedbifurcated contact element wherein the prongs tiex in two directions toprovide edge-engaging lo-w-resistance contact making pressure.

The novel features which I believe to be characteristic of my inventionare set forth with particularity' in the appended claims. My inventionitself, however, together with further objects and advantages thereof,will best be understood by reference to the following description takenin connection with the accompanying drawings, in which:

FIGURE l is a top plan view of one form of the connector element of thepresent invention shown unmounted. It should be appreciated that theconnector element shown may be mounted in any suitable insulatingreceptacle or, for example, on a printed circuit board;

yFIGURE 2 is a side view of a mating connector element showing in detailthe depending legs or electrical contacts to facilitate mounting of theelement on a printed circuit board;

FIGURE 3 is a side view of -a connector element of FIGURE 1 showing anelement especially adapted for mounting in a suitable insulatingreceptacle and provided with a soldering lug or wire wrap terminal atone extreme thereof;

FIGURE 4 is a bottom plan view of a connector element identical to thatshown in FIGURE 2 but rotated 90 to show it in mating relationship tothe contact of FIG- URE 3;

FIGURE 5 is a cross-sectional view of the contact elements shown inFIGURE 3 taken along lines 5-5 of FIGURE 3, showing the overlappinginterfacial areas in greater detail;

FIGURE 6 is an end view of the connector shown in FIGURE Z taken fromthe contact element end showing in greater detail the overlappingrelation of the contact elements;

FIGURE 7 illustrates the stamped blank metal piece from which theconnector elements, such as those shown in FIGURES 3 and 4, are formed;

FIGURE 8 illustrates the stamped blank metal piece from which theconnector elements, such as those shown in FIGURES 1 and 2, are formed;

FIGURE 9 is an end view of the metal blank shown in FIGURE 7, taken fromthe contact element end;

FIGURE 10 is a fragmentary end view of the metal blank shown in FIGURE8, taken from the contact element end;

FIGURE 11 is a perspective view of a pair of electrical connectorelements constructed in accord with one modication of the presentinvention, the elements being shown in mating interengagingrelationship;

FIGURE 12 is a cross-sectional view through lines 12-12 of FIGURE 11illustrating the large interfacial contact area of the interengagingcontacts;

FIGURE 13 is a perspective view of a pair of electrical connectorelements according to another mode of the present invention, theelements being shown in interengaging relationship;

yFIGURE 14 is a cross-sectional view through lines 14-14 of FIGURE 13again illustrating the large electrical contact area presented by thecontact elements of the present invention;

'FIGURE 15 illustrates the contacts of FIGURE 13 in interengagingrelationship and as mounted in the printed circuit board members;

FIGURE 16 is `a perspective view of another embodiment of the presentinvention illustrating the connector element as shown in FIGURE 2 butwith rotated or twisted electrical contact elements;

FIGUR-E 17 is an end view of the electrical connector element shown inperspective in FIGURE 16I taken from the contact element end;

FIGURE 18 is a perspective View of a pair of electrical connectorelements, as illustrated in FIGURE 16, shown `in mating, interengagin-grelationship;

IFIGURE 19 is a cross-section view through the contact elements of thetype shown in FIGURE 18 with the contact elements in interengagingrelationship, illustrating the large interfacial contact area;

FIGURE 20 is a perspective view of a pair of interengaging electricalconnector elements illustrating the connector element as shown inFIGURES 3 and 4 but with rotated or twisted electrical contact elements;

lFIGURE 2.1 is a cross-sectional view through lines 21-21 of FIGURE 20illustrating the large electrical contact area between the interengagingcontact elements;

FIGURE Z2 is a perspective Viewl of a pair of interengaging electricalconnector elements illustrating another modication of the presentinvention; and

FIGURE 23 is a cross-sectional View taken through lines 423--23 ofFIGURE 22 showing the electrical contact area presented between theinterengaging contact ele-ments.

Referring now more particularly to 4FIGURE 1 of the drawings, there isshown an electrical connector element, indicated generally at 1. Theconnector element 1 is preferably stamped and formed from a sheet ofelectrically -conductive brass material although it should be understoodthat any suitable material having the requisite electrical andmechanical characteristics would be satisfactory `for the connectorelements.

As shown in FIGURES 7 and 9, the connector element v1 is initiallystamped out of a hat metal sheet which process contributes tomanufacture of the element on a high volume basis. The originallystamped connector element 1 is provided with a soldering lug or wirewrapping post 2 at one end thereof and is bifurcated at the other endthereof to provide a pair of spaced apart contact elements 3 and 4. Thespaced apart contact elements 3 and 4 have substantially hat 'facingsurfaces 7a and 7b, respectively, the surfaces being so shaped toprovide a large electrical contact face to interengaging contactelements.

During the stamping operation a small portion of the metal at the baseof the slot 6' is cut away from the remainder of the metal stamping ateither side. The portion 5 is then bent or formed to a positiondisplaced 90 from the plane in which it originally lay to form a Y lug'5, which lug forms a stop or positioning member for the connectorelement 1 so that said element may be inserted within an insulating body(not shown) in a casual Y fashion and always come to rest in a positionthat allows l tion the connector element 1 may be twisted slightly topermit the recesses 8 and 161 to engage said ilange section to therebytix the element 1 with respect to the insulating body.

The contact elements 3 and 4 are then deformed to the positions show-ntherefor in FIGURES 1 and 3. As is illustrated, contact elements 3 and 4are each bent slightly outwardly away from the central longitudinalplane of the connector element 1 to a position where the inner planaryfaces 11 and 12 of said elements 3 and 4 lie in substantially the samefvertical plane. The elements 3 and `4 are bent slightly inwardly,toward the central axis of the connector element 1 as illustrated inFIGURES 3 and 5 so that an overlapping area, indicated generally at 14,is presented wherein the inner marginal area of each of the faces 11 and1.2 of the contact elements 3 and 4, respectively, are in contact alongsubstantially the length of the contact elements.

The electrical connector elements 1, illustrated in FIG- U-RES l and 3,are of a design such that when one element is placed in end-to-end,contact element-facing relationship with one another connector element,the contact elements 3 and 4 will interengage with relative ease andprovide a good electrical connection between said pair of connectorelements. It will be readily seen that the contact elements 3 and `4must be urged slightly apart when interengaging with a second pair ofcontact elements. When a pair of contact elements 3 and 4 areinterengaged in electrical connecting relationship, the inner planar`faces 11 and 12 do not overlap. It should be observed that the materialfromy which the connector elements is manufactured should have a yieldpoint at least in excess of that force required to urge the elements 3and 4 slightly apart when in electrical engagement with another pair ofelements so that when the pair of connector elements are disengaged, thecontact elements 3 and 4 will return to their original overlappingpositions, as deiined above.

A modied connector element, as shown generally at 1S in FIGURES 2 and 4,is especially adapted vfor use with printed circuitry. The connectorelement 15 may also be stamped from a sheet of material having suitableelectrical and mechanical characteristics.

The stamped connector element 15 has a body portion 13 and a pair oflegs 16 and 17 depending from said body portion `13. The element 15 isslotted at 1S on the opposite half thereof to define a pair of contactelements 2t) and 21. The facing surfaces 7c and 7d of contact elements2t) and 21 are substantially flat along substantially the length of thecontact to thereby provide a large electrical `Contact area to similarlyshaped contact elements.

The contact elements 2t! and 21 are deformed after stamping to thepositions shown in FIGURES 2 and 4. As shown, the contact elements 2i)and 21 are each bent slightly out-wardly-near their base positions-awayfrom the central longitudinal plane of the connector element 15 to aposition where the inner planar faces 22 and 23 of the elements lie insubstantially the same plane. The contact elements Ztl and 21 are thenbent slightly inwardly toward the central axis of the connector element15, as illustrated in 'FIGURES Z and 4, so that an overlapping area,indicated generally at 24, is presented wherein the inner marginal area`of each of the faces 23 and 24 of the contact elements 20 and 21,respectively, is in contact along substantially the length of thecontact elements.

The contact elements 1 and 15 illustrated in FIGURES 1 and 2 areillustrated in FIGURE 11 in mating, interengaging relationship in whichrelationship an electrical path is completed between said contactelements. The contact elements 1 and 15 are shown of themselves and areillustrated as mounted in the conventional insulating body. It should beunderstood that the contacts in use will always be mounted .in areceptacle of some form to facilitate their use in the most convenientform. The combination of contact elements 1 and 15 of FIGURE l1 would,for example, electrically connect a conventional circuit with a printedcircuit. The contact is preferably mounted on a printed circuit board,as shown generally in FIGURE 15, with the depending legs 16 and 17making electrical Contact with the circuit leads of the printedcircuitry. The contact 1 is preferably mounted, for example, in aconventional insulating base or plug with wire leads extending from thesoldering lug or wire wrap post 2.

FIGURE 12 is a cross-sectional view through line 12-12 of FIGURE 11which is the contact-engaging area of the contact elements 1 and 15. Asillustrated, the contact elements 3 and 4' of the contact 1 engage thecontact elements and 21' of the contact 15 in intimate electricalconnecting relationship. The contact elements 3', 4', 20 and 21 are thesame as Contact elements 3, 4, 20 and 21 as shown in FIGURES 1 and 2except that they `are bent away from the body plane in oppositedirections therefrom. It should be understood, of course, that it isimmaterial in which direction the contact elements are bent away fromthe body plane. The contact elements 3', 4', Ztl' and 21', wheninterengaged, are spread slightly. The spreading action of the contactelements when engaged with a mating pair of contact elements gives riseto a vise effect acting on the mating elements. This mechanical viseeffect enhances the mechanical interference between the mating contactsand ha'.- the net effect of facilitating the mechanical interconnectionthus tending to sustain the connection and inhibit any casualdisconnection of the contacts. It should be understood that a pluralityof contacts may be mounted on the same circuit board or within the sameinsulating body in mating relationship to provide a convenientreceptacle having facilities for a plurality of interconnectingelectrical circuits.

It will be noted from the cross-sectional view of FIGURE 12 that a largeinterfacial electrical contact area is presented between the contactelements 3', 4', 20' and 21', which contact elements are made in accordwith the present invention. The large electrical contact area of theinterengaged contact elements of the present invention is incontradistinction to the contact area present on the connecting devicespresently commonly employed. It will be noted that the presentconnecting devices provide a line contact or point contact between thecontact elements. At best, the present connecting elements may providefacial contact of a flat element (in the case of the male-female typecontact), but normally such connecting devices have the disadvantage ofbeing dissimilar in construction as pointed out above. The at facingsurfaces 7fz-bcd of the contact elements further provide the samecontact area along substantially the entire distance of theinterengaging contact elements. It is apparent that the large contactarea between the contact elements gives rise to an inherently efficientelectrical contact. Contact resistance is considerably reduced and theprobability of a foreign, non-conducting substance shorting out thecontact is likewise reduced with the net result that a more reliable andefficient contact is made.

FIGURES 13 and 14 are illustrative of the interengaging relationship oftwo identical contacts 15 of 111e present invention. It will be observedthat one-half of the total surface area of the contact elements, perunit of length thereof, is in electrical contact with the mating Contactelements. Such relatively large contact areas provide a highly efficientelectro-mechanical connection between connectors manufactured in accordwith the present invention. FIGURE 15 illustrates a connector element 15of the type shown in FIGURES 2 and 4 as mounted on a conventionalprinted circuit board. Each of the connector elements 15 is shownmounted in a board 25. As shown, the legs 16 and 17 of each of theConnector elements 15 are inserted into and extend through each of thecircuit boards to protrude -a slight 6 distance beyond the oppositesurface of the board. Each of the legs 16 and 17 of the connectorelement 15 perforates and extends through an electrically conductiveprinted ribbon or circuit member to establish preliminary electricalcontact therewith. A deposit of solder 2.7 or some other suitableelectrically conductive material that will establish and maintain apositive ele-ctrical connection between the legs 16 and 17 and theribbon element 26 is placed about the protruding portion of the legs 16and 17 to thereby electrically and mechanically connect the ribbon 26and legs 16 and 17. The connecting elements 15 are positioned on thecircuit board 25 in a position such that the contact elements 20' and 21of each of the connector elements 15 will extend beyond the edge 28 ofeach of the boards 25, so that the contact elements are in a position tointerengage with mating contact elements of the connector elements to bejoined therewith. The abutting ends 28 of the printed circuit boards 25serve as a positive stop to prevent insertion of one pair of contactelements into the mating pair too great a distance, which would resultin damage to the elements. It should be observed that a conventionalinsulating body (not shown), into which connecting elements 1 as shownin FIGURES 1 and 3 may be inserted, would serve as the stop orpositioning member to provide for proper engagement of the matingcontact elements.

Another modification of the present invention is illustrated in FIGURES16 through 19. A connector, indicated generally at 30, is comprised ofthe same body portion 13 as the connector elements shown in FIGURES 2and 4, and depending legs 16 and 17 for the purpose of attaching theconnector to a printed circuit board, as shown generally in FIGURE 15.

Contact elements 31 and 32 are of the same general type and outlineconfiguration as the contact elements 2t? and 21 of connector element15, except that the elements 31 and 32 are twisted with respect to themain body portion 13 of the connector element 30.. The contact elements31 and 32 are each disposed in. -a separate plane, parallel to eachotherthe same as disclosed with regard to the elements of connector15-each of the planes of the elements 31 and 32 being rotated withrespect to the plane of the main body portion 13 of the connectorelement 30.

FIGURE 17 is an end view of the connector element 3i) shown in FIGURE 16taken from the contact element end of said connector. FIGURE 17illustrates more clearly the twisted, overlapping relationship of thecontact elements 31 and 32. It should be understood that the connectorelements 30 of FIGURE 16 may be provided with the prong-shaped solderinglug or wire wrap post for connection of the wire leads to the element 30rather than the body 13 and depending legs 16 and 17 as shown therein.Such construction is shown for illustrative purposes only.

FIGURE 18 illustrates a pair of connector elements 3), such as shown anddescribed in conjunction with FIG- URE 16, in interengaging matingrelationship..

FIGURE 19 is a cross-sectional view through the interengaging contactelement area of a pair of interengaging connector elements 30, of thegeneral type shown in FIGURES 16 through 18. FIGURE 19 again illustratesthe relatively large electrical contact area presented by theinterengaging contact elements 31 and 32 of the present invention.

FIGURE 20 illustrates another embodiment of the present invention. Aconnector element, indicated generally at 34, has a connecting post orlug 35 to which the wire leads to be electrically and mechanicallyconnected to said post are soldered, wrapped or fastened by some othersuitable means. Oppositely disposed recesses 36 are provided within thebody portion of the connector 34. The recesses 36 are employed to assistin positioning the connector element 34 within a suitable insulatingbody (not shown). It should be understood that said recesses 36 mayengage a flange portion within said insu- 7 lating body and be lockedthereto by twisting over said flanges to non-removably position saidelement 34 within the body. An upraised lug 37 is provided on theconnector element to longitudinally position the connector element 34within the insulating body (not shown). The connector element 34 may beinsertedin one method of assemblyinto a slot provided in an insulatingbody. The lug 37 would then engage an abutting portion within the slotof the insulating body, which abutting portion Would serve to preventthe connector element 34 from passing completely through the slot in theinsulating body. The lug thus, in an insulating body as generallydescribed, would serve to position the connector element 34 Within saidinsulating body so that the contact elements 38 and 39 of said connectorelement 34 would project beyond the insulating body the desired amountand in such position be adapted for interengagement with a similarconnector element to provide an electrical connection between twoelectrical circuits. The contact elements 38 and 39 of each of theconnector elements 34, respectively, are disposed in a separate planeparallel to each other but rotated from the plane of the main bodyportion of the connector elements 34.

FIGURE 21 is a cross-sectional view taken along line 21-21 of FIGURE 20and is illustrative of the relatively large electrical contact areapresented by the interengaging contact elements 38 and 39, respectively.

Another modiiication of the present invention is shown in the embodimentof FIGURE 22. In this modication the connector elements, indicatedgenerally at 40, are each provided With a pair of contact elements 41and 42. The contact elements 41 and 42 are each bent away from the mainbody portion of the connector elements 40 in stepped fashion such thateach of said contact elements is disposed in a separate plane spacedfrom, but parallel to, the plane of the main body portion of theconnector element 40. Each of the contact elements 41 and 42 of theconnector elements 40 has a rounded portion 45 adjacent the end of eachof said contact elements. When the contact elements 41 and 42 of a pairot' connector elements 40 are in interengaging relationship, the roundedportions 45 of each of the contact elements, respectively, will beadjacent each other, lying in the sarne general plane of contact. Thisfeature of construction gives rise to a camrning action between thepairs of contacts to facilitate engagement and disengagement of thecontacts without damage to the contact elements or their relatedstructure.

FIGURE 23 is a cross-sectional View taken through lines 23-23 of FIGURE22. The large electrical contact area of the identical mating connectorelements 4i) occurs at the plane of intersection of the rounded portion45 of the contact elements 41 and 42, respectively.

While I have shown and described specific embodiments of the presentinvention, it will, of course, be understood that other modificationsand alternative constructions may be used without departing from thetrue spirit and scope of this invention. I, therefore, intend by theappended claims to cover all such modications and alternativeconstructions as fall within their true spirit and scope.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An electrical connector comprising a pair of contact members, each ofsaid members having a body portion lying in a predetermined plane andhaving a bifurcation to provide a pair of spring contact elementsextending from said body portion, each of said elements having inner andouter parallel planar broad surfaces and top and bottom edge surfacesbetween said broad surfaces, said elements of each pair being offsetlaterally of each other to dispose the inner broad surface of eachelement in substantially the same plane, said elements of each pairbeing positioned with portions of said inner broad surfaces inoverlapping relation, lead means at the outer ends of said elements foreffecting electrical engagement of the contact elements of each pair inan end to end direction, said elements of each pair expanding duringsaid interengagement to contact said other pair of e1ements under springtension.

2. An electrical connector as dened in claim 1 in which said planarbroad surfaces of each pair of contact elements are disposed in parallelrelation to said plane of said respective body portion from which saidpair extends.

3. An electrical connector as delined in claim 2 in which said planarbroad surfaces of each pair of contact elements are disposed in angularrelation to said plane of said respective body portion from which saidpair extends.

4. An electrical connector comprising a pair of contact members, each ofsaid members having a body portion lying in a plane normal to the planeof said other body portion, each of said body portions having abifurcation to provide a pair of spring contact elements extending fromsaid body portion, each of said elements having inner and outer planarbroad surfaces and top and bottom edge surfaces between said broadsurfaces, said elements of each pair being offset laterally of eachother to dispose the inner broad surface of each element insubstantially the same plane, said elements of each pair beingpositioned with portions of said inner broad surfaces in overlappingrelation, lead means at the outer ends of said elements for effectingelectrical engagement of the contact elements of each pair in an end toend direction, said elements of each pair expanding during saidinterengagement to engage an edge surface of each element of one pairwith said inner planar broad surface of each element of said other pair.

References Cited in the ile of this patent UNITED STATES PATENTS2,125,816 Reynolds Aug. 2, 1938 2,762,022 Benander et al Sept. 4, 19562,779,011 Deakin Jan. 22, 1957 2,953,766 Clewes Sept. 20, 1960 2,994,056Fox July 25, 1961 3,011,143 Dean Nov. 28, 1961 3,012,221 Deakin Dec. 5,1961 FOREIGN PATENTS 218,200 Switzerland Apr. 16, 1942 538,801 GreatBritain Aug. 18, 1941 1,187,074 France Mar. 2, 1959 1,247,715 France VOct. 24I 1960

1. AN ELECTRICAL CONNECTOR COMPRISING A PAIR OF CONTACT MEMBERS, EACH OFSAID MEMBERS HAVING A BODY PORTION LYING IN A PREDETERMINED PLANE ANDHAVING A BIFURCATION TO PROVIDE A PAIR OF SPRING CONTACT ELEMENTSEXTENDING FROM SAID BODY PORTION, EACH OF SAID ELEMENTS HAVING INNER ANDOUTER PARALLEL PLANAR BROAD SURFACES AND TOP AND BOTTOM EDGE SURFACESBETWEEN SAID BROAD SURFACES, SAID ELEMENTS OF EACH PAIR BEING OFFSETLATERALLY OF EACH OTHER TO DISPOSE THE INNER BROAD SURFACE OF EACHELEMENT IN SUBSTANTIALLY THE SAME PLANE, SAID ELEMENTS OF EACH PAIRBEING POSITIONED WITH PORTIONS OF SAID INNER BROAD SURFACES INOVERLAPPING RELATION, LEAD MEANS AT THE OUTER ENDS OF SAID ELEMENTS FOREFFECTING ELECTRICAL ENGAGEMENT OF THE CONTACT ELEMENTS OF EACH PAIR INAN END TO END DIRECTION, SAID ELEMENTS OF EACH PAIR EXPANDING DURINGSAID INTERENGAGEMENT TO CONTACT SAID OTHER PAIR OF ELEMENTS UNDER SPRINGTENSION.